Duplicated monitored instances in SQL Monitor

I have installed SQL Monitor to monitor two database instances hosted in a two node failover cluster, I have one instance per cluster node:
RPT01\DB01
RPT02\DB02

We have seen that when we move a database instance to the other node, SQL Monitor add an additional instance to the monitor, e.g. RPT01\DB02. However if we move back the instance to the original node, the additional instance created is still there. So, now we have:
RPT01\DB01
RPT01\DB02
RPT02\DB01
RPT02\DB02

How can I fix this to get back to the original and valid state; what I am doing wrong?

The issue is because in previous SQL Monitor versions, the software did not distinguish when was monitoring a cluster, it only detected SQL Server instances, this new version makes the distinction and as this implementation was made migrating from a previous SQL Monitor version, the first time I moved the cluster resources from one node to the other, then this behavior arose.

What I am doing is eliminating the monitored servers and letting SQL Monitor new version detect them from the scratch.